Heat source cover

ABSTRACT

A cover for a heating body comprising a thin wall at least partially screening the heating body from a region outside of the heating body. The thin wall comprises a polymeric material being substantially rigid and substantially resisting permanent deformation at temperatures from 100° C. to 130° C., the polymeric material further substantially resisting infrared absorption at wavelengths corresponding to black-body temperatures of 200° C. to 500° C.

FIELD OF THE INVENTION

The present invention relates to a cover for a heat source, inparticular for a heating body, such as hot liquid containing tanks,radiators and the like, comprising a thin wall screening at leastpartially the heat source from the outside.

BACKGROUND OF THE INVENTION

These covers of this type are already known for a long time, inparticular covers in enamelled, lacquered or chromium-plated plate orcast iron.

These covers involve technological problems with respect to theirforming and colouring. Moreover, they are not transparent for infraredradiation emitted by the heating device when this device is for examplea heating body, more particularly a domestic stove. After having coveredthe latter, the ambient atmosphere can only be heated by convection.

JP-A-59202337 discloses a protective grate which is to be placed on theradiation surface of a radiator, the grate being of polyester and havinglarge openings for allowing the heat to pass therethrough.

SUMMARY OF THE INVENTION

An object of the present invention is to work out a cover as describedhereinabove which avoids the aforesaid drawbacks while being notexpensive and easy to manufacture. Advantageously, this cover will allowto increase the comfort of a heating body by allowing radiation heating.

In order to solve these problems, a cover as described hereinabove wasprovided, according to the invention, wherein said thin wall is based ona polymeric material having a high rigidity and a good deformationstrength at a temperature above 100° C., and wherein the used polymericmaterial has a low infrared absorption at wavelengths corresponding toblack-body temperatures of 200° C. to 500° C. Covered with such a cover,a heating body will be able to heat the ambient atmosphere not only byconvection but also by radiation, which results in considerably higherenergy savings and an improved impression of comfort. Advantageously,the used polymeric material shows these properties at a temperatureabove 130° C., preferably above 200° C.

By deformation strength it has to be understood that the wall frompolymeric material resists to a permanent deformation. When a mechanicpressure is for example exerted onto this wall, it does not bend orpossibly it may inflect in an elastical way while taking in afterwardsits initial position again. At the indicated temperature, the wall isalso not subject to flow.

The use of a non-metal material offers the big advantage of a simple andwell known manufacture process, for example by moulding, thermoformingor by an analogous process. This allows also to stain the polymericmaterial in the mass with a colorant or a pigment and hence to omit theapplication of a coloured coating. Finally, a large freedom of design isachieved by such a cover from polymeric material, which is anon-negligible quality for such an element serving to mask another.

A cover of this type is moreover relatively light and easy to handle.

According to an embodiment of the invention, the plastic material is apolyester resin. Advantageously, the polyester resin is selected withinthe group comprising bisphenol A fumarates, isophthalic resins andchlorendic resins.

In a particularly advantageous way, the polymeric material is anoriented crystal polymer, for example a lyotropic liquid crystal polymersuch as Kevlar, or a thermotropic liquid crystal polymer such asRhodester CL. In this case, a cover resisting to temperatures of 350° C.might even be taken into consideration.

In a very particular embodiment of the invention, the thin wall is madeof a composite material containing said polymeric material. In thecomposite material, the polymeric material may be reinforced withfibres, for example a.o. with glass fibres, carbon fibres, liquidcrystal polymers. In certain applications, the composite material mayalso be composed of at least one possibly reinforced layer of saidpolymeric material and of at least one layer of another materialsupporting the previous layer.

Other particular embodiments of the invention are indicated in theclaims.

Other details and particularities of the invention will become apparentfrom the description given hereinafter by way of non limiting exampleswith reference to the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a domestic wood stove equipped with acover according to the invention.

FIGS. 2, 3 and 4 show two variant devices for fixing a cover accordingto the invention onto a heating body.

FIG. 5 shows a perspective view of a central heating boiler whose wallsare covered according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the different figures, identical or analogous elements have beengiven the same reference numerals.

FIG. 1 shows a usual wood stove 1 which rests onto two legs 2 supportingthe heating body 3.

In front of the heating body a cover 4 according to the invention isplaced which consists of a protective panel 5 supported by the heatingbody 3 through the intermediary of attachment elements 6, only three ofwhich are shown schematically in FIG. 1. As further seen in FIG. 1,panel 5 may have a continuous surface.

The illustrated panel is made from a polyester resin selected preferablyamongst bisphenol A fumarates, isophthalic resins and chlorendic resins.As isophthalic resins, mixtures of isophthalic acid with maleicanhydride or fumaric acid may in particular be mentioned. As chlorendicresins, mixtures of chlorendic anhydride or acid with maleic anhydrideor fumaric acid may in particular be mentioned.

The protective panel 5 according to FIG. 1 is for example manufacturedby thermoforming. It is transparent for infrared beams. This propertyallows to fix the cover relatively far from the heating body.

Two possible ways of fixing the panel 5 onto the heating body 3 areillustrated in FIGS. 2 and 3. The attachment elements 6 are arranged inthe space between the heating body 3 and the covering panel 5. In FIG.2, the attachment element consists of two U-shaped braces 7 and 8. Thelateral arms 9, 10 and 11, 12 of each of these braces are connected tothe body 3 or respectively to the panel 5, for example by means ofrivets or by any other appropriate means. The webs 13 and 14 of the twobraces are arranged one in front of the other and maintained on adistance from each other by a spacing element 15 from a heat insulatingmaterial, for example from porcelain. A clamping element 16, which ispreferably also made of a heat insulating material, keeps the spacingelement 15 secured between the two braces 7 and 8.

In FIG. 3, the attachment elements 6 are composed of a short U-shapedmetal profile 17. One of its arms 18 is maintained at a distance fromthe heating body through washers 21 and 22 from a heat insulatingmaterial, for example from porcelain, and it is clamped against thesewashers by a bolt 19 going through these washers and through an openingin the heating body, and by a nut 20 arranged within the heating body 3.The other arm 23 of the profile 17 is maintained at a distance frompanel 5 by a washer 24 from an insulating material, for example fromcork. This entity of arm 23, washer 24 and panel 5 is rivetted in ausual way by means of a rivet 25.

Another way of fixing the panel 5 onto the heating body 3 is illustratedin FIG. 4. This way of fixing is similar to the one illustrated in FIG.2 but easy to remove. In this embodiment, the rivet 16 is replaced by amagnet 35 fixed to one of the braces, for example to brace 8 by anattachment element 36. In the fixed position, this magnet 35 is forexample housed in a metal recess 37 of brace 7. This removable way offixing is especially feasible according to the invention thanks to thelow weight of the panel according to the invention.

Of course, other ways of fixing the cover onto the heating body can beprovided.

The cover might also be rendered self-supporting. In this case, thepanel 5 rests, as indicated chain-dotted in FIG. 1, with one of itsedges 27 directly onto the ground. It is then advisable to use apolymeric material reinforced with fibres, for example with glassfibres, so that the panel is composed of a composite material.

In FIG. 5 can be seen a hot water boiler 42 covered with a wall 38 madeaccording to the invention.

It has to be understood that the present invention is in no way limitedto the hereabove described embodiments and that many modifications canbe applied thereto without leaving the scope of the present patent.

The covering panels according to the invention can for example bymanufactured in different ways by using for example a liquid crystalpolymer.

Such a lyotropic polymer, such as Kevlar, can be atomized, in solution,into two Teflon-coated dies rotating around their axis and the solventcan be evaporated. The polymer is formed against the wall of revolutionas a result of the centrifugal force and the evaporation of the solvent.

It is also possible to spray a thermotropic polymeric powder, such asRhodester CL, within the two aforesaid rotating dies heated to therequired temperature for obtaining an adequate orientation of the liquidcrystals (about 302° C. for Rhodester CL).

A spray process under rotation onto the die with an adhesion resultingfrom an electrostatic charge may also be appropriate.

Finally, in order to produce a composite material, different successivespraying steps can be provided, for example in the following order :

a) spraying of a coloured coating of short fibres or grains (thickness1/10 mm),

b) spraying mineral Wollastonite fibres in bulk or short polyethylenefibres simultaneously with a polyester resin according to the invention(thickness 1 mm),

c) spraying an expansible resin of the polyurethane+fibres type(insulator) (thickness 5 to 8 cm),

d) spraying Kevlar or carbon fibres together with a resin of thealimentary type (about 6 mm).

Afterwards, the obtained product may possibly be cut into differentpanels destined as cover for heating bodies.

We claim:
 1. A cover for a heating body comprising a thin wall at leastpartially screening the heating body from a region outside of theheating body, the thin wall comprising a polymeric material which issubstantially rigid and which substantially resists permanentdeformation at temperatures from 100° C. to 130° C., the polymericmaterial further substantially resisting infrared absorption atwavelengths corresponding to black-body temperatures from 200° C. to500° C.
 2. The cover as claimed in claim 1, wherein the polymericmaterial is substantially rigid and substantially resists permanentdeformation at a temperature above 130° C.
 3. The cover as claimed inclaim 1, wherein the polymeric material is a polyester resin.
 4. Thecover as claimed in claim 3, wherein the polyester resin is selectedfrom the group comprising bisphenol A fumarates, isophthalic resins andchlorendic resins.
 5. The cover as claimed in claim 1, wherein thepolymeric material is an oriented crystal polymer.
 6. The cover asclaimed in claim 1, wherein the thin wall is made from a compositematerial containing said polymeric material.
 7. The cover as claimed inclaim 6, wherein the composite material is composed of afibre-reinforced polymer.
 8. The cover as claimed in claim 7, whereinthe fibre-reinforced polymer includes reinforcing fibres selected fromthe group consisting of glass fibres, carbon fibres and liquid crystalpolymer fibres.
 9. The cover as claimed in claim 6, wherein thecomposite material is composed of at least one layer of the polymericmaterial and of at least one layer of a supporting material supportingthe layer of the polymeric material.
 10. The cover as claimed in claim1, wherein the thin wall includes a protective panel placed in front ofa heating body in a self-supporting way.
 11. The cover as claimed inclaim 1, wherein the thin wall includes a protective panel which isfixed to a front region of the heating body and which is thermallyinsulated therefrom.
 12. The cover as claimed in claim 1, wherein thethin wall is moulded.
 13. The cover as claimed in claim 1, wherein thepolymeric material of said wall is mass-stained with a coloring agent.14. The cover as claimed in claim 1, wherein the polymeric material issubstantially rigid and substantially resists permanent deformation at atemperature above 200° C.
 15. The cover as claimed in claim 9, whereinthe polymeric material is fibre-reinforced.
 16. The cover as claimed inclaim 12, wherein the thin wall is thermoformed.
 17. The cover asclaimed in claim 1, wherein the polymeric material is substantiallyrigid and substantially resists permanent deformation at temperaturesfrom 100° C. to 350° C.
 18. The cover as claimed in claim 1, wherein thethin wall has a continuous surface.